1. Field of the Invention.
The present invention relates to a dual direction indicator and, more particularly, to a dual direction indicator for selectively indicating one or both of two opposed directions.
2. Description of the Prior Art.
There are many applications where it is necesssary to convey a message of anticipated direction change or to signal others to change directions. In road construction and repair, a direction change is often required in the form of a detour around the construction or repair area. For this purpose, a commonly used detour sign is the type constructed from reflectorized materials which are illuminated by auto headlights or the like. However, wih present high speed travel on modern freeways, reflectorized signs may not provide adequate warning time.
One system for providing adequate warning in advance of a detour is to illuminate a direction arrow which will be visible beyond the headlight distance. Unfortunately, driving hypnosis often leads to a state of semiconsciousness and the continuously illuminated sign may be overlooked.
To overcome these problems, arrays of flashing lamps and sequentially energized signs have been developed heretofore. In some such systems, a plurality of lamps arranged in opposed arrowhead configurations and an arrow shaft common to both arrowheads is sequentially energized to indicate the desired direction. An example of this type of system is that disclosed and claimed in U.S. Pat. No. 3,479,641 issued Nov. 18, 1969, to Gerald C. Summers for Sequential Direction Indicator. Other systems are disclosed in U.S. Pat. Nos. 3,622,980 and 3,747,063 issued Nov. 23, 1971, and July 17, 1973, respectively, for Directional Warning System and Bistable Circuit Controlled Sequential Lamp Indicator, respectively.
Unfortunately, while the systems of the above patents are effective in providing the desired warning for oncoming vehicles, the circuitry for energizing the lights is elaborate and complex and the resulting systems are therefore expensive. Because of such expense, many State agencies are reluctant to purchase such systems and they have not gained the widespread acceptance that circumstances would appear to dictate.